Magnificent cleaning jobs are done by an expert cleaner. One who is not looking at cleaning as a chore but rather a science. This is exactly how I started Clean and Pink Cleaning Company, 11 years ago. My mantra being “it’s a science not a chore”™. The science is proper cleaning technique and understanding products. This shower door had permeated water spots all over it. I halved 10 lemons and washed all the shower glass with them. Then I cleaned the shower glass doors with Alcohol and water, using a squeegee getting all excess water off the glass and drying the glass, completely. Lastly, I treated the glass doors with a polishing agent (rainX). Not using for a good 6-8 hours after treating. This allows the glass to “cure” The excess water will not permeate rather bead and run down the glass shower. Moderate use (2 showers per day) once per quarter. Heavy use (4 showers per day) about every 5-6 weeks or when needed. This will not work on massive glass permeation, rather that’s a different topic entirely.